I tried, but it does not work.
Here codes:

this.parent.OleMMess.compose
THIS.PARENT.OleMMess.recipdisplayname=this.Parent.c_nguoinhan
this.parent.OleMMess.msgnotetext=this.Parent.c_noidungthu
this.parent.OleMMess.msgsubject=this.Parent.c_chudethu
this.parent.OleMMess.Attachments.Add("ADD.TXT",0,1,"d:\dtd40x\ADD.TXT")

I get a message error following:

Member Attachments does not evaluate to an object.

&&Press OK button, get other message

OLE Idispatch exception code 0 from MAPIMessages: Invalid session.